Caracterización genética de la neoplasias mieloides mediante secuenciación masiva

Abstract

Myeloid neoplasms (MN) are a group of hematological diseases in which myeloid hematopoiesis is altered. This group includes acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), chronic myeloproliferative neoplasm (MPN), and myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN). MN are diseases with a high genetic heterogeneity, therefore a large number of cytogenetic and molecular techniques are necessary for their characterization from this point of view, which is essential for the diagnosis, prognostic stratification and clinical management of MN patients. Specifically, in AML, the treatment of each patient is based on the prognosis, administering more intensive therapies to high-risk patients. However, even patients with a favorable prognosis suffer high relapse rates. Therefore, an optimization in the stratification would help these patients to benefit from more adequate treatments. Nextgeneration sequencing (NGS) is a technique that allows the simultaneous analysis of a different types of variants (substitutions, CNV and translocations) in a large number of genes. Although its application in MN is growing, there are aspects to be addressed regarding its clinical usefulness. In this context, the aim of this study was, on the one hand, to describe the implication of the use of the NGS in the diagnosis, prognosis and treatment of patients affected by MN, and on the other hand, to improve the prognosis of patients affected by low-risk AML through the analysis of genetic and clinical biomarkers. Two cohorts were analyzed using NGS gene panels. Cohort 1, consisting of 121 patients affected by MN and cohort 2, of 27 AML patients with mutated NPM1 gene and without the FLT3-ITD variant, classically classified as low risk patients. The development of a score which allows to evaluate the pathogenicity of specific variants detected in oncohematological diseases, improved variant classification of patients from cohort 1, affected by MN. In cohort 1, 278 pathogenic or probably pathogenic variants were found in 84% of patients. As for structural alterations, NGS detected 82% of the abnormalities identified by conventional cytogenetic methods. In comparison with conventional methodology, NGS changed the diagnosis of seven patients and the prognosis of 15. Moreover, using the genetic data obtained, 44 patients could have been included in clinical trials, which had finally occurred only in four. As for the patients affected by AML in cohort 1, ten of them relapsed, of which six gained or lost variants in the relapse. As for the AML patients with mutated NPM1 and non-mutated FLT3-ITD from cohort 2, the presence in the diagnosis of the variant FLT3D835 and a NPM1 qPCR value ≥0.1% after the first cycle of chemotherapy were associated with a higher probability of relapse, increasing the risk when both variables were concomitant. In contrast, when the NPM1 variant was present in the main clone at diagnosis, the probability of relapse was lower. NGS optimized the diagnosis, prognosis and treatment of patients affected by MN, in comparison with conventional methodology. Furthermore, it helped to differentiate subgroups of different risk within a favorable prognosis subgroup of AML. In conclusion, NGS proves to be of great clinical utility in patients affected by MN, ultimately improving their clinical management.